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Impact of respiratory pattern on lung mechanics and interstitial proteoglycans in spontaneously breathing anaesthetized healthy rats
Author(s) -
Moriondo A.,
Marcozzi C.,
Bianchin F.,
Passi A.,
Boschetti F.,
Lattanzio S.,
Severgnini P.,
Pelosi P.,
Negrini D.
Publication year - 2011
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/j.1748-1716.2011.02317.x
Subject(s) - tidal volume , ventilation (architecture) , anesthesia , respiratory physiology , medicine , lung , respiratory rate , work of breathing , respiratory system , pulmonary compliance , breathing , lung volumes , mechanical ventilation , heart rate , blood pressure , mechanical engineering , engineering
Aim: The aim of this study was to investigate the effect of different pattern of spontaneous breathing on the respiratory mechanics and on the integrity of the pulmonary extracellular matrix. Methods: Experiments were performed on adult healthy rats in which different spontaneously breathing pattern was elicited through administration of two commonly used anaesthetic mixtures: pentobarbital/urethane (P/U) and ketamine/medetomidine (K/M). The animals (five per group) were randomized and left to spontaneously breath for 10 min (P/U‐sham; K/M‐sham) or for 4 h (P/U‐4 h; K/M‐4 h), targeting the anaesthesia level to obtain a tidal volume of about 8 mL kg −1 body wt. At the end of the experiment, lung matrix integrity was assessed through determination of the glycosaminoglycans (GAGs) content in the lung parenchyma. Results: Compared with K/M, anaesthesia with P/U cocktail induced: (1) a higher respiratory rate and minute ventilation attained with lower P a CO 2 ; (2) a higher pressure‐time‐product and work of breathing per minute; (3) a lower static lung compliance; (4) an increased activation of lung tissue metalloproteases; and (5) greater extraction of pulmonary interstitial GAGs. Conclusions: This study suggests that the breathing pattern induced by the different anaesthetic regimen may damage the pulmonary interstitium even during spontaneous breathing at physiological tidal volumes.